Computer Science > Networking and Internet Architecture

Abstract: We analyze the performance of TCP and TCP with network coding (TCP/NC) in
lossy networks. We build upon the framework introduced by Padhye et al. and
characterize the throughput behavior of classical TCP and TCP/NC as a function
of erasure probability, round-trip time, maximum window size, and duration of
the connection. Our analytical results show that network coding masks random
erasures from TCP, thus preventing TCP's performance degradation in lossy
networks. It is further seen that TCP/NC has significant throughput gains over
TCP.
In addition, we show that TCP/NC may lead to cost reduction for wireless
network providers while maintaining a certain quality of service to their
users. We measure the cost in terms of number of base stations, which is highly
correlated to the energy, capital, and operational costs of a network provider.
We show that increasing the available bandwidth may not necessarily lead to
increase in throughput, particularly in lossy networks in which TCP does not
perform well. We show that using protocols such as TCP/NC, which are more
resilient to erasures, may lead to a throughput commensurate the bandwidth
dedicated to each user.